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By Michael Moats, Weston Hartzell

The stable domestic supply of gallium, indium, and germanium has been identified as a critical need for the USA. Electric arc furnace dusts processed to recover zinc produce a process residue that could be a potential source of these critical materials. An industrial zinc leach residue was characterized to determine the predominant mineral phases and leached with common mineral acids. Atmospheric agitated leaching using sulfuric acid and hydrochloric acid were examined to determine the extractions of gallium, indium, and germanium as a function of concentration, temperature, and time. Extractions of gallium were found to be similar to iron in all experiments. The maximum percentage of Ga, Ge, and In leached into solution were 82%, ~100%, and 89%, respectively.

Aug 8, 2023

By E. Lovera

ABSTRACT: The current study analyzes the feasibility of an odd operation: to obtain, using a properly tailored drilling and blasting scheme, blocks suitable for the production of dimension stone from tunnel driving. Clearly, a compromise must be found between the rate of progression and the achievement of workable blocks. As a case study, a civil work under consideration in northern Italy was examined. The work was planned to cross a conglomerate that has traditionally been locally exploited for the production of highly prized paving and lining stones with excellent strength and aesthetic features. Natural exposures and mined-out quarries were available for tests. The relevant rock data are given, blast designs are shown (within the limitations of contour accuracy), and the test program is described.

Jan 1, 2011

By J. Rajala

The Kupol mill facility processed a high grade free milling gold/silver ore containing 28.2 g/t Au, 324.8 g/t Ag and approximately 0.5% pyrite during 2008 operation. Gold predominantly occurs a selectrum in the ore and silver is predominantly present in the forms of acanthite, stephanite, pyrargyrite and proustite. Mill start-up was in mid-May 2008 and the mill reached the design throughput of 3 000 tpd in October. The ore was ground to approximately 70%?53 microns. A Knelson Concentrator recovered 9.8% gold and 0.5% silver. The gravity tails reported to a cyanidation circuit that has 14 hours pretreatment and 116 hours leaching. The slurry from cyanidation was then processed by counter current decantation (CCD) thickening to wash and separate the leach residue from the pregnant leach solution. Precious metals are recovered fromthe pregnant solution using the Merrill-Crowe process. The washed CCD leach residue slurry is treated with calcium hypochlorite to destroy cyanide and then sent to the tailings impoundment. Leaching is performed with a new technology called ?CELP? (CANMET Enhanced Leach Process). The Kupol mill overall gold and silver recoveries for 2008 were 95.4% and 85.6% respectively, which were 2.8% and 7.5% higher than targets. Gold and silver extractions in the leach circuit were 94.2% and 84.5% respectively. Leach profiles indicated that gold extraction reached a plateau in the 4th tank while minor silver dissolution occurred in the 5th tank. With the CCD circuit included, total gold and silver extractions increased to 95.4% and 86.6%, respectively. Optimization of the leaching strategy made it possible to reduce sodium cyanide concentration to as low as 410 ppm without compromising precious metals extractions. Silver was effectively leached from the refractory silver minerals because CELP produced more oxidized mineral surface relative to the conventional cyanidation leached mineral surfaces. The average cyanide consumption for 2008 was 1.3 kg/t. The new leaching technology proved to be very robust and performed efficiently even with changes in feed grade and ore mineralogy. Laboratory experiments produced results that were indicative of plant performance. The robustness of the technology and the laboratory test work contributed to the success of the Kupol mill start-up.

Jan 1, 2009

That gold will dissolve in sodium hyposlphite solutions is known from the lixiviation of silver and gold ores.The gold will dissolve only in small quantities. According to Stetefeldt, if gold leaf is treated for a time with sodium hyposlllphite solutions of varying strengths solution takes place in every instance, the deviation in quantity being very slight.In order to form hyposulphite double-salts, the gold must become oxidised, the oxygen being derived from the air absorbed by the solution. Consequently, it is the quantity of free oxygen in the solution by, which the reaction is determined, as for one equivalent of gold dissolved one equivalent of caustic soda is set free.

Jan 1, 1901

By N. Melnyk, H W. Habgood

The conventional low temperature process for extracting' helium from natural gas involves liquefying the whole gas stream in order to remove the relatively small fraction of helium. A process based on the selective diffusion of helium through a semi-permeable barrier is, in principle, more economical and flexible, particularly for the treatment of small re-serves and low concentrations. The well-known permeability of glass to helium offers the possibility of such a diffusion process and McAfee of the Bell telephone Laboratories showed in 1958 that practical separations could be achieved by passing natural gas over bundles of fine capillary glass tubing. Developmental studies have been carried out involving larger units and more extended field tests than those of McAfee. Fine capillary tubing of Pyrex glass 0.0035 in. diameter was prepared by drawing ordinary 6 mm. laboratory tubing in a furnace. Extraction units were pre-pared containing about 10,000 such tubes, 4 ft. long and cemented inside

Jan 1, 1961

By Jafar Safarian

Bauxite is the main raw material used for the production of alumina (Al2O3) through the well-known commercial Bayer process. This process has significant challenges such as limitation in using low-grade bauxites as they contain significant amounts of impurities such as Fe, Si, Ti. The Bayer process residue, which is known as red mud, is also a global environmental challenge due to huge amount of this low value residue production. An alternative sustainable process with high potential to solve these problems and produce valuable and consumable by-products is a pyrometallurgical-hydrometallurgical process in which the low-grade bauxite ore is treated through a smelting-reduction process, yielding iron alloys and a calcium-aluminate slag. Alumina is then produced from the slag by hydrometallurgical treatment. In the present work, the reduction of pellets produced from different bauxite ores by hydrogen is studied and it is shown that complete iron oxides reduction is possible. Further smelting and smelting-aluminothermic reduction of the reduced pellets show that iron and silicon ferroalloys can be produced, in addition to a proper slag for alumina extraction.

By S. M. C. Santos

Preliminary bench-scale studies were carried out on the leaching of a zinc sulphide concentrate from Somincor, Portugal, and the purification of the resulting pregnant solution using solvent extraction techniques. The sulphide concentrate contained 36% Zn, 36% S, 2% Fe and 4% Cu. The leaching was carried out with sulphuric acid in the presence of ferric sulphate as the oxidant. Important leaching parameters, such as the effect of reaction time, the solid-liquid ratio, temperature and concentrations of acid and oxidant, were investigated. After leaching, the recovered solution was contacted with an organic phase containing Acorga 5640 to remove the copper. Subsequently, the removal of iron from the leaching solution was achieved with a mixture of Cyanex 272 and TBP. This solvent mixture was relatively selective for iron over zinc. The stripping of the loaded solvent was performed with 200 g/L H2SO4. Six countercurrent extraction stages achieved a separation of about 99% of the iron from the leaching solution. The iron-free leachate can be further treated to recover minor metals by cementation, and finally, zinc by liquid-liquid extraction. The advantages of the suggested process relative to the traditional jarosite process are discussed.

Jan 1, 2006

By K. Osseo-Asare

LIX63 in combination with DNNS selectively extracts nickel and/or cobalt from acidic leach liquors with pH values as low as 1.0. Nickel/cobalt and cobalt/nickel selectivities are achieved by varying the relative concentrations of LIX63 and DNNS. Increasing LIX63 concentration retards both extraction and strip-ping rates while DNNS has the opposite effect. Slope analyses of equilibrium data indicate that both LIX63 and DNNS are present in the extracted complexes. Examples of possible flowsheets are presented.

Jan 1, 1978

By M. J. Steffens

ESPLIM is a novel separation technique that combines the advantages of solvent extraction and electrostatic dispersion but its application in the extraction of nickel by the direct solvent extraction route and the effect of high electrostatic field on the stability of organics have not been explored. These were investigated in this study and it was found that the technique allows 97% extraction of the nickel in a single stage compared with 3 stages by the conventional solvent extraction. Also, three months of exposure to 5.0 kV under simulated operational conditions had no adverse effect on the stability of organics.

Jan 1, 2005

By Ting An Zhang, Chengzhi Jiang, Xiujing Zhai, Feng Xie

The extraction and concentration of nickel from aqueous solutions by emulsion liquid membranes (ELMs) using tributylphosphate (TBP) as extractant has been investigated in this research. The emulsion liquid membrane consists of a diluent (kerosene), a surfactant (Span 80), a mobile carrier (TBP), and a stripping solution (ammonia solutions). Important factors influencing the separation process including membrane composition, feed composition, and mixing speed have been examined. The results show that more than 90% of nickel in the feed solution could be extracted by ELMs under the experimental conditions, indicating the feasibility to use the designated ELMs to detoxify nickel-containing industrial waste solutions.

Jan 1, 2014

By Z. H. Khan, A. K. Saha, D. D. Akerkar

The possibility of extracting nickel from a low-iron, highly siliceous nickel ore of Indian origin using roast reduction followed by an ammonia leaching process has been examined. The ore used in the investigation contained 0.82 wt% Ni, 6.20 wt% Fe3O4, 12.04 wt% MgO and 60 wt% SiO2. Phase changes in the constituent minerals on heating were studied by differential thermal analysis which revealed endothermic peaks at 110 and 695 degrees C and an exothermic peak at 810 degrees C. Significant process variables in studies of roast reduction include the amount of reductant, the temperature of reduction and chemical kinetics. Maximum nickel extraction was achieved by reducing the ore with 10 wt% fuel oil at 750 degrees C. The reduced ore was given a preconditioning treatment in concentrated ammonium hydroxide solution to oxidise most of the metallic iron and was then leached in aqueous ammoniacal solution at ambient temperature to dissolve nickel. This gives 88.5% extraction of nickel as soluble ammine complexes.

Jan 4, 1992

By Vladimir Lobanov, Vladimir Skorohodov, Andrew Evdokimov, Ural State Technical University 19, Boris Radionov

"The bulk of raw materials in metallurgy of secondary platinum metals are the wastes such as multilayered ceramic-metal systems, e.g. the spent catalysts of the chemical and petrochemical industry, automobile catalysts, etc. Due high chemical resistance of a ceramic basis the extraction of platinum metals by leaching even at very fine crushing is poor. The study of sorption leaching of platinum and a palladium from the spent automobile catalysts are carried out. The average content of PGM is 0.5%. A few methods of raw materials sampling were compared: 1) direct hydrometallurgical leaching of platinum metals from the fine-grained catalyst and atomic absorption analysis of the obtained solutions; 2) fusion to a metal or sulphidic collector of precious metals with the alloy analysis by direct spectrometry; 3) fusion with dissolution of a precious metals collector and atomic absorption analysis of PGM in solutions. Leaching allows detecting out no more than 90% of a palladium and 80% of platinum. Fusion to a collector gives the best results at the chemical ending. Researches on sorption leaching are executed. Under optimum conditions the extraction of platinum metals to concentrates is comparable with similar indicators of collector fusion.The large part of raw materials in metallurgy of secondary platinum metals are the multilayered or tridimensional ceramic-metal systems, in particular the spent catalysts of the chemical and petrochemical industry, automobile catalysts, ceramic-metal condensers, etc. The content of the sum of PGMs can be from hundreds grams per ton to several percent. For processing of such materials the hydrometallurgical methods of platinum metals leaching by various reagents are used commonly. High chemical resistance of the ceramic basis covering the metal particles causes low recovery even at very fine grinding. Other fundamentally different method of catalysts opening includes dissolution of the ceramic basis in the solutions of hydrofluoric acid and the subsequent recovery of platinum metals from insoluble residue. Application of this method is associated to use of corrosive medias and appropriate equipment. Fusion of the specified materials with collecting of PGM by copper, nickel or lead at the specialized enterprises provides higher extraction in semiproduct. At the same time, complexity and duration of the subsequent extraction of platinum metals concentrates causes high total cost per unit. Thereby this method is economically acceptable only for rather poor raw materials (no more than 0,1%). Undoubtedly, that the raw materials with the high content of PGM are reasonable to process by individual technology. In the present work the processing of some kinds of ceramic-metal raw materials, particularly automobile catalysts (neutralizers) with various collectors at the conditions of a target fusion are investigated."

Jan 1, 2008

By R. J. Traill

Introduction Following the discovery of high-grade deposits of pitchblende in the Great Bear Lake area of the Northwest Territories by Mr. Gilbert LaBine in May, 1930, samples were submitted to the Mines Branch for examination and investigation as to suitable methods of treatment (1). The purpose of this paper is to present, briefly, the results of the investigative work conducted on the ores and an outline of the methods developed for the extraction of the radium content and recovery of the by-products. The paper is presented in two parts. Part I gives a review of the history of radium production and of the principal processes used in other countries. Part II describes the work and gives the results of the Mines Branch investigation. Part 1-Radium Production In Other Countries Historical Outline Uranium was discovered in 1789, and more than a century later Madame Curie, while studying the physical properties of this element, observed that the ore of uranium exhibited greater activity than the pure uranium com-pounds she had prepared and traced the cause to the presence of a new element which she named radium. Eventually, research proved radium to be a disintegration product of uranium, and always present in uranium ores.

Jan 1, 1933

By M. Tanaka, H. Narita, T. Fuchikami, K. Morisaku, K. Nagao, T. Yoshida, K. Kuroda

The effect of various N-substituents on the performance of amide-containing tertiary amine compounds in the extraction of Rh(III) from HCl solutions was investigated to optimize the structure of these compounds for industrial use. It was found that N-2-ethylhexyl-bis(N-di-2-ethylhexyl-ethylamide)amine and tris(N-di-2-ethylhexyl-ethylamide)amine, which have long, branched alkyl chains, were suitable for Rh extraction, because they were soluble in a practical diluent (80 vol% n-dodecane?20 vol% 2-ethylhexanol) and stable against highly concentrated HCl/Rh solutions, and showed high selectivity for Rh(III) over Pd(II) and Pt(IV).

Jan 1, 2014

By James R. Evans

Orange County, adjacent to the populous and industrialized Los Angeles area, is the fastest growing county in California and is second only to Los Angeles County in total population (figure 1). In addition to an equable climate and a burgeoning economy, there is room in Orange County for growth and expansion. Growth over the past decade has resulted in rapid development of industrial tracts, housing areas, and shopping and commercial centers, mostly in former agricultural areas. The value of new building in 1972 was a record amount-over I billion dollars (figure 2). Problems relating to the proper direction of growth are the concern of both government and the private sector. The intelligent and efficient use of areas to be developed requires planning for the conservation and protection of the County's natural beauty and for the orderly development of natural resources. The availability of sand and gravel, which is used in many phases of construction, will be a major controlling factor in the future of the County.

Jan 1, 1974

By J. P. Hager

The formation of the vapor complex AgFeC14 (g) baa been identified and its thermodynamic properties determined. The vapor pressure of silver chloride can be enhanced by a factor of 15-20 due to the formation of the vapor complex. The vapor pressure of both AgCl (g) and AgFeC14(g) were measured using a double-zone transpiration .technique. Gibbs free energies have been determined for the vapor transport reactions. Laboratory kiln tests were conducted to confirm the enhanced recovery of silver through the formation of the AgFeC14(g) vapor complex and to indicate the opportunities for process development using this new vaporization chemistry.

Jan 1, 1985

By Urs Peuker, Thomas Mütze, Thomas Leißner, Inga Osbahr

"Mining in the Ore Mountains (Germany) has taken place for hundreds of years and in several stages. Each stage produced its typical tailing. According to the former state of the art of the processing much valuables could not be extracted. This was caused by complex interlocking of the minerals, low grades, or by upgrading processes not sensitive enough for small particle sizes. Thus the processing of these fractions was uneconomically. Modern technical possibilities and rising metal prices bring these tailings disposals into focus for the processing of strategic metals. Mining disposals can be classified in heaps with coarse, low grade rock, which did not undergo a processing, slags and fly ash from smelting, and tailing disposals from mineral processing. The latter is under investigation to integrate them into a geographic information system. The mineral processing of the material will be part of the database besides information about geographic location, structure, amount of valuables, and details of ownership of the heap. The tailings disposals are composed of coarse, low grade, interlocked particles from density separation processes, medium size particles, which are tailings from flotation, and fines with liberated valuables, which did not undergo flotation. Therefore mineral processing of these disposals comprises the separation of liberated gangue by classification, beneficiation of locked valuables with density separation, liberation of valuables by grinding, and beneficiation of liberated valuables with flotation. The presented work shows the results concerning the composition of one exemplary heap and results of the classification as well as of the preconcentration tests achieved with material from this heap."

Jan 1, 2014

By Yun Guo, Min-Min Lin, Bing Xie, Hong-Yi Li

The extraction of vanadium from vanadium-containing APV-precipitated wastewater by W/O microemulsion system was studied. In the N263/n-heptane/isoamyl alcohol/NaCl microemulsion system, N263 played double functions of cationic surfactant and extractant to form microemulsion in n-heptane, and isoamyl alcohol was added in the microemulsion as a cosurfactant. The extraction of vanadium by W/O microemulsion systems effectively accelerated the extraction and improved the extractatability because of the enormous increase in the micro-interfacial surface area. Due to ion association with extractant, vanadium was extracted into the microemulsion phase. The influence of different parameters on the extraction ratio (E%) were investigated, including the volume ratio of aqueous phase to microemulsion, surfactant concentration, pH value of the feed solutions, cosurfactant concentration, extraction time as well as temperature. In optimum conditions, the extraction ratio (E%) can reach 97.2%.

Mar 1, 2018

By Hassan Saalman, Mahmoud Mahmoud, Omneya El Hussaini

The Ferruginous sandstone ore was obtained from Ramlet Hemeyir area, Southwestern Sinai, Egypt, was found to contain 10% rare earth elements (REE). A representative sample has been subjected to sulfuric acid agitation leaching. About 93% of the REE content was released by mixing the ground sample to -100 mesh with concentrated H2SO4 at solid/liquid (S/L) ratio of 1/2 for 5h at a temperature ranged from 250 to 300o C. The REE was precipitated from the prepared sulfate leach liquor of pH 1.0 by adding 35% oxalic acid at 25o C. The precipitation yielded 98% REE. For selective separation of yttrium, the rare earth cake was leached with 31.5% nitric acid. Next, the aqueous solution was contacted with di-(2-ethylhexyl) phosphoric acid (D2EHPA) where 98% yttrium extraction was achieved. Stripping was done with hot H2O (80o C). Finally, a precipitation with oxalic acid was done followed by ignition at 950o C. A yield of 95% yttrium oxide was produced.

Jan 1, 2014

By Hsing Kuang Lin

Extraction of zinc from chloride solution with dibutyl butylphosphonate (DBBP) in Escaid 110 has been investigated. The distribution coefficient of zinc was found to be independent of equilibrium pH. This independence indicates that the mechanism of the extraction may be solvation. Slope analysis for the system of dilute zinc chloride solution reveals that two moles of DBBP react with one mole of zinc. A series of tests were conducted to bring DBBP to its full loading capacity and the analysis of the results confirms this stoichiometric factor of 2. Extraction isotherms were established by varying either the AIO ratio or the concentration of zinc in the aqueous feed. Both curves were found to be identical.

Jan 1, 1990